Bailway-tbaefic-contbolling appabattjs



Jul 19 1927.

y H. A. WALLACE RAILWAY TRAFFIC CONTROLLING APPARATUS July 19,1927. I

H. A. WALLACE RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Sept. 24, 1925 2 Sheets-Sheet 2 ioA ,branch pipes 17 and 41.

Patented July 19, 1927.

UNITED STATES PATENT OFFICE.

HERBERT A. WALLACE, OF EDGEYVOOD BOROUGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH AND SIGNAL COIVIPNTI, OF SWISSVALE, PENNSYLVANIA, A COR- PORATION F PENNSYLVANIA RAILWAY-TRAFFIC-CONTROLIING APPARATUS.

Application filed September 24, 1925.

My invention relates to railway traffic controlling apparatus, and particularlyto apparatus of the type comprising train carried governing means responsive .to traffic conditions. More particularly, my invention relates to governing means for causing an automatic application of the brakes upon a change trom less restrictive to more restrictive traffic conditions in advance of the train. One object of my present invention is the provision, in apparatus of the type described above, of a novel arrangement of apparatus for relt-iasingl the brakes after such automatic application. i

I will describe two iornis of railway traffic controlling apparatus embodying my invention, and will then point out the novel features thereof in` claims.

In the accompanying drawings, Fifi't 1 is a view, partly diagrammatic, illustrating one form of railway traffic controlling apparatus embodying my invention. Fig. 2 is a view illustrating a modified form of the apparatus shown in Fig. 1 and also embodying my invention, l

Similar reference characters ret'er to sinnlar parts in both views.

Referring firstto Fig. 1, the reference character L designates a brake application valve comprising a pressure chamber 21 and a valve chamber 3, separated by a reciprocable piston 4. The valve chamber 3 1s constantly supplied with fluid pressure, usually air, from a source not shown in the drawing,

`through pipe 1. The piston 4 is provided with a restricted orifice 4a through which the pressure supplied to chamber 3 may gradually flow into chamber 2. Chamber 2 is connected with a pipe 2n which leads to two When these two pipes are blanked, pressure admitted to chamber 2 through orifice 4a, combines with the force exerted by a spring 5 to move pinston 4 to the right against the pressure in chamber 3. fVVhen chamber 2 is connected with atmosphere, however, the piston 4 1s moved to the left by pressure in chamber 3. The piston 4 operates a slide valve 6 controlling a plurality of valve ports.

The reference character 5() designates a pipe which is normally supplied with Huid pressure and which is arranged to apply the brakes when pressure in this pipe is reduced.

Serial No. 58,308.

lhen the piston 4 is in its normal or righthand position, pipe 50 is blanked by valve 6. Then piston 4 is in its reverse or letthand position, pipe 50 is connected with atmosphere through ports 26 and 40, to cause an automatic brake application.

The reference character H designates a relay valve comprising a. valve stem 7 provided with an armature 10 and a winding 11. The winding 11 is controlled by traffic conditions in advance of the train so that under safe traffic conditions the winding 11 is energized from a source not shown in the drawing. Under dangerous traffic conditions the winding 11 is de-energized. Vhen winding v11 is energized, valve stem 7 is moved downwardly and fluid pressure then iiows from a source not shown in the drawing through pipe 9, valve H, and pipe 12 to chamber 14 of repeater valve J. Pressure thus supplied to pipe 12 also charges the timing reservoir 13. The repeater valve J comprises a valve stem controlled by a diaphragm 14a subjected to the pressure in chamber 14. When chamber 14 is supplied vith fluid pressure as just described stem 15 is forced downwardly to blank pipe 17 and to connect pipe 18 with atmosphere through port 16. Then winding 11 of valve H becomes Cle-energized valve stein 7 rises, disconnecting pipe 9 from pipe 12 and connecting pipe 12 with atmosphere through port 8. Pressure in timing reseivoir 13 and in chamber 14 of valve J is therefore gradually dissipated to atmosphere. After a time interval the stem 15 of valve J rises, thereby connecting pipe 17 with pipe 18.

Pipe 18 is normally connected through a suppressing valve M, pipe 24, a manually' operable release valve A, and pipe 37, with a stop reservoir 38.

The suppressing valve M comprises a chamber 21 containing a piston 21a. This piston carries a plunger 23 and a valve 20. Pressure in chamber 21 is controlled by an acknowledging valve K and an acknowledging reservoir 31 associated therewith. Vhen the acknowledging valve K is in its normal position, reservoir 31 is supplied with fluid pressure from a source not shown in the drawing through pipe 30. Vhen the valve K is reversed and valve L is in its normal position, the pressure in reservoir 31V is supplied, through valve K, pipe 33, port 27 of Valve L and pipe 25 to chamber 21 of suppipe .#12,

pressing valveM. Piston 21a is therefore moved upwardly, blanking pipe 18 and suplilyngpfluid .pressure troni aj source not shown in the drawing through pipe 19 and valve 2O to pipe 24 and therefore to stop reservoir 38.

The release valve A is a manually operable valve which may be located in. such position that the valve is accessible to the engineman onlyY Vwhen llieftrain isat rest. is has al readyY been stated, when the valve is in its normal position pipe Qll is connected With pipe VJhen valve ii isreversed, howeveiglpipeI-lhis blanked andrpipe 24 is connected with pip-42 through pipe all and a check valvel.

lillhen valve L is in the .reverseposition, pipe l1 is connectech.through port 29 with Pipewlis. connected with a' pilot Yalve tl -ivhich is operated by the enginenianii; brake falve andis closed only vvhe'n the enginenians brake valve in the lap position. lt'ivill be manifesttherefore that ii- .valve (l `is open when .the application `valve iL reverses, chamber Q will be connected. directly Awith, atniosphere through the path just traced through valve G.

shown inthe drawing, relay valve ll is energized. Glianiher A14;` of vahieJv and timing reservoir 13 areltheretore charged with tluid pressure so that valve .l is operated lo blank pipei17. Valve K is in its normal Aposition so that reservoir 31 is charged with tluid pressure. Suppressing valve M is also in its normalposition so that valve 2O is closed and pipe 2l isiconnected with pipe 18. The brake application valve iris iii vits-normal position so that pipe Ll1 is: blanhed-hv valve and pipe 5() is also blanltcd so that the brakes are released. Valve li in itsI normal position thereby conncffting pipes l ant. 37 together. Reservoir 38 is thereiore Connected with atmos plicre. vl/Talve G, controlled by the engine inans brake valve is open.

Yl will nowassuine that relay Valve il becomes file-energiscd as by ka change 'troni ler-H to more rcstrii consiitions ier` advance. uChamber 14 oi" alve J and timing reservoir 1B are therefore connected with atn'iosphere. After a time interval stem 15 ot valve J rises, connecting. pipe 17 with stop reservoir 3S throim'h valves Manci A. The consequent reduction inv the pressure in chamber .i2 .ot valve'L causes that valve to reverse, connecting. pipe .50 .with 'atmosphere land causing an automatic application ot the braltes.

`.The reversal---ot valve Lcconnects pipe 41 vWit-hiatinospliefe through port 29, pipe es?, ,and valve G., The reversal ,of .valve L and i th eretore [the pressure inl ychamber 2 Leashes therefore connected with atmosphere through tivo paths; one through vpipe 17, valve il, pipe 18, valve M, pipe .2f/l, valve pipe 37, poi S18 ot' valve L, and port 39; and the other through pipe l1, por*-` 2?) ot valve L, pipe and valve t1 .ln order to release the brel-:es the engineinaii lirstmoves his brake valve to the lap position, thereby closing valve G. IBipe 4t2 is theeifore blanlied at valve G. rlhe engineman then reverses valve l. This operatioirot valve l( discharges, into pipe 2323, the pressure to which the acknowledging res-ervoir 31 hadpreviously been charged. Valve li is in the reverse position however, and pipe 325 is therefore blanhed by slide valveG. The engineman then operates valve A., tliei'eiiy disconnect-ing reservoir 3C lfroin pipe 2i and connecting pipe 2Liivith pipe through pipe tl, and check valve lle. lt will be vseen that this operation ot valve A blanks all avenues ot escape tor pressure Lt'roni chamber Pressure admitted to `chamber 2 through the restricted oriliee e therefore grathrall)7 builds up to the value necessari)v to restore piston L to its normal position. lllhen this operation ot valve L .talieslplacepipe ll is blanlied, pipe 37 is blanked, and pipe 5() is lilanlted. vrlheblanliing olf pipe 5) makes it possible'tor the en gineinan to release his liralies. l"

ihe niovenient ojl valve'L to 'its normal position also connects pipe 3&3 ivith pipe The pressure suppliedvto pipe 255:3 troni the aclinoivledgingl reservoir o1 there'iore itlovvs into chamber 2l oi the suppressing valveV M, lifting piston miic plunger 28,t and opening valve 20.

l 8 is thereforeblanliedand :tluidy presis supplied to pipe 2l through valve 20.

yThis pressure is supplied through valve A, .pipe velet, and check valve ii-5, to pipe'li, but

pipe l2 is blanked at slide valve t3 :,-1o that the pref ure thus supplied to pile Q4 has no tunction until the engineman restores valve ii to its normal position. llhen he does so, pressure in pipe 2li Vtlovvs through valve A to pipe 37. 4This pipe is blanked at slide valve (i and (the pressure thus snpplietl thereto charges stop reservoir 38 with .tluid pressure. latter a time interval'tlie pressure supplied to Chamber 21 ol' valve M is dissipated to atmosphere through a Arestrictive o iiice fl' he piston 21Zi therefore returns toits lower position.l connecting pipe Sovith pipenl, hnt'tl'iis operation has 'no effect on' the valve L because the stop 'reservoir. is .no'vv charged With iiuid pressure is not reduced. The engineman can therefore restore the acknowledging valve 'l to its normalI position and can operatey his engineinvans bralte valve. tothe release or running A.positions because Ythe. consequential `opening ot valu Gcanliave" no `eii`ect oiijthe brake application vaive Ysince With valve )'-lfni'tlie lli) cri

normal position valve G is disconnected from pipe 41.

lt should be pointed out that if, after a brake application has been incurred, the valve H again becomes energized, so as to blank pipe 17 at valve J, the engineman can release the brakes, without operating the release valve A, by simply moving his enginemans brake valve to the lap position to close valve Gr. This will blank pipe 42, and pipe 1 7 being blanked at valve J, the pressure will build up in chamber 2 to restore the valve L to its normal position.

lt should also be pointed out that an automatic application of the brakes can be prevented if the engineman takes proper action upon a change from less to more restrictive trattic conditionsi I will assume for example that the apparatus is in the position illustrated in the drawing, and that valve H becomes (le-energized. After a time interval valve J opens to connect pipe 17 with pipe 18. If, prior to the operation of valve J, the engineman operates valve K, the pressure in reservoir 31 flows into chamber 21 of suppressing valve M. The resulting operation of valve M blanks pipe 18 and charges stop reservoir 38 with fluid pressure. The hlanking of pipe 18 prevents a reduction in the pressure in chamber 2 and therefore the Vvalve 'L does not operate when valve J opens.` lhen the pressure supplied to chamber 21 becomes dissipated to atmosphere through orifice 22 the suppressing valve M is restored to the condition in which it is illustrated in the drawing thereby connecting pipe 18 with pipe 24. But while valve 2() vvas open stop reservoir 88 fas charged with fluid pressure and therefore when pipe 18 becomes connected with pipe 24 thcpressure in chamber 2 is not reduced and the application valve L therefore remains in its normalv position. l t will be plain from the foregoing that if the engineman takes suitable action by ope wating the acknowledging valve K a brake application can be prevented even though valve H becomes cle-energized.

'IA will new assume that an automatic application of the brakes has been incurred by de-energization of valve H without the acknowledgement by the engineman te prevent operation of the brake application valve L. I will also assume that the engineman has brought the train to a stop and has proceeded as explained hereinbefore to release the brakes by operation of valves G, A and K. I will further assume that valve A is left in the reverse position so that pipes 44 and 24 are connected together and pipe 37 is blanked. If, under these conditions, the engineman should return to his cab and attempt to proceed with his :train by moving his enginemans brake valve away from the lap position, valve G will immediately Open. W'hen valve M returns to its normal position fluid pressure from chamber 2 will iminediately escape through pipe 17, valve J, pipe 18, valve M, pipe 24, release valve A, pipe 44, check valve 45, pipe 42, and valve tl to atmosphere, and the brake application valve L therefore will reverse to apply the lnakes. lt will therefore be seen that the appara us is so arranged as to require the engineman t restore valve A to its normal position before he can proceed after an automat-ic application of the brakes.

l will new assume that an automatic application of the brakes has been incurred, that the valve G is closed, and that the engineman has reversed valve A in an attempt to release the brakes but that valve L is still in the reverse position. l will further assume that due to a change to proceed conditions in advance, valve H becomes energized. tltein of valve J is therefore driven downwardly. lV ere it not for the check valve 45 fluid pressure would then escape from chainber through pipe 41, port 29 in slide valve t3, pipe 42, pipe 44, valve A, pipe 24, valve hl, pipe 18, and valve J to atmosphere through port 1G. With the check valve 455 interposed between pipes 42 and 44 however, this escape of fluid pressure is prevented and the engineman is therefore permitted to release his brakes by proper operation of release valve A even though valve H becomes energized after an automatic application of the brakes due to (ile-energization of this valve.

'teferring now to Fig, 2, a. relay R is controlled by traffic conditions in advance in such manner that under safe traffic conditions the relay is continuously energized. Vhen traffic conditions` in advance of the train are dangerous, however, the relay R is cle-energized briefly and is then ire-energized.

In the form here shown the relay R is controlled by a shoe 7 2 supported in the frame of the locomotive and arranged to co-operate with trackway ramps, one of which illustrated at Q, and which are located at intervals along the trackway. These ramps are controlled by traliic conditions so that when traffic conditions in advance of a ramp are safe the ramp is withdrawn so as not to engage shoe '72 as the train passes. lf" traflic conditions are dangerous, however, the ramp is moved into a position wherein it is engaged by the shoe 72 of a passing train. The shoe 72 is biased to the position shown in the drawing by a spring 71. When the shoe is in the position a Contact 75-73-74 is closed. Then shoe 72 engages a ramp, the shoe is lifted to open the contact 73-74. Relay R is connected with terminals B and C of a suitablesource of energy not shown in the drawing in series with the contact 75-73-74. It follows that relay R isnormally energized, but is de-energized for a brief interval under dangerous traliic conditions when the train passes a ramp Q.

titl

rrssocia'ted with the main relay R is a stick relay S which is controlled in part by a manually operable circuit controller D. T his circuit controller comprises a cylinder il@ containing, a piston el? biased to an upper position by a lspring` 48. Rigidly attached to the piston 47' is a movable contact finger 4i). A second movable contact finger 5l manually operable by the engineman is attached to finger 49 by means ot a spring 62. Under normal conditionsI the piston 47, under the influence oft the springl 48, occupies such. position that cont-act 49 is closed and contact 51 is open. lt, however. cont-act 51 is closed, spring,` G2 overcomes the torce exerted by sprin` i8 and moves piston l? downwardly to open contact e9. Due to the time required tor the escape ot' air under piston l?, a brie?.

interval ot time elapses after the closing' of contact 5l and before the opening' ot contact fl-.9. lt will therefore be plain that contact.

can he closed for a briet' interval and reopened vwithout opening,` contact 49, but that it contact 5l is permanently closed contact- 49 will be held open.

The stick relay S is provided with a pickup circuit which may be traced from terminal B through wire 57, contact 5l ot circuitcontroller D, wires 58 and 55. winding of relay S'. toA terminal C. A stick circuit is also provided for this relay from tcrn'iinal B, through trontcontact 52 o'i' relay R, wire i'rout contact all ot stiel relay S, wire 55, winding;Y ot relay S to terminal C. lt will tl creiiore be plain that it the stick relay is once energized by operation oi"- the circuit controller D, the relay will 'be maintained in its energized condition over its stick circuit as long' as relay remains energized.

rilhe relay valve H is provided with a winding; ll which is supplied with energy over a. circuit which may he tracedtrom terminal B. through contact 49 of circuit controller D, wire. 59, front Contact 60 ot relay S,`wire 6l, winding 1l et valve ,ll to terminal C. lllhen winding; 1l is energized the valve stem 7 of valve H is moved downwardly to bla-nk pipe 63. TWhen. windingl ll is Cle-energized, however, the stem 7 is moved upwardly so that pipe 6?) is connected with atmosphere through port 8. Pipe G3 is one ot' the branch pipes connected through pipe 2"" with chamber 2 'or a brake applicationV valve L similar to valve L of Fig. 1. rlhe other branch pipe 64 connects withY a pipe 65 whichis normally blanked by slide valve G" otvalveli. Pipe 64e also communicates with pipe G6 which is normally blanked by valve A. vWhen valveL reverses, pipev 65 is connected with pipe 4-2, which pipe is constantly connected with the stopK reservoir 38 and with the pilot valve G. Whenivalve A is in its normal position.pipe'lQ` isconnected, through pipe 6'?, valve'A, and port 68 to atmosphere. When valveAcV is re-y versed,.however, pipe 67 is connected with pipe 66.

Pipe'O, which controls 'the ibrakes. is blanked when the valve L is in the normal position and is connected with atn'iosphere when this valve is reversedexactly as already explained in connection with l.

As shown in the drawing relay R is energized, circuit controller D occupies its normal position, relay S is energized over its stick circuit, and valve H is energized, thereby blanking pipe 63. The brake application valve L is in its normal position and the brakes are released. rihe release valve A is in its normal Vposition and valve G is open. 'lfhe stop reservoir 3S is therefore connected with atmosphere. l will now assume that relay R becomes cle-energized briefly as by engagement of shoe 53 with a ramp The opening' ot front contact 52 thereon deenergizes relay S, which latter rela'y opens. le] hen lrelay R again becomes energized the closimgl ot contact 52 can not pick up relay S and theretore can not have any effect upon the governing apparatus, unless the change in traiiic conditions was acknowledged by proper operation ot circuit ciontroller D. Assuming that'no such operation ot the circuit controller tal-:es place, the openingl ot :front contact ot relay S interrupts the circuit tor winding l1 otl valve H. (S2- is therefore connected with ati'nospherc and pressure Afrom chamber 2 flows through pipe (53 and valve H to ati'nosphere. Brake application valve L therefore reverses, connecting pipe to atmosphere and causingv an automatic application ot the brakes. lt. should be pointed out that it the'enginomim attempts to defeat the purpose of relay R by taste-.ning circuit `controller D in its operated position, thatl is, in such position that con- Y tact fill is closed so that the pick-up circuit tor stick relay S is complete, contact 49 will be opened. thereby interrupting the circuit 'for valve H and causing an automatic application ofthe brakes.

lllhen valve L is reversed chamber 2 is connected with atmosphere through pipes (Sil and port 3Q slide valve t, pipe l2 and valve G. VPipe is also connected with atmi` "iliere through valve Yl'twill theretot lain that zitter valve L is moved to it o position it can not'l e restored to its no .'mal position simply by aga-in energizinp; valve H". ln order to releasethe brakes after an automat-ic applicationot the brakes the engineman first operates circuit controller-D to energize stick relay S. Relay S thenremains closed as long asrelay R is energized. Theclosing of contact otrelay S completes the circuit for valve El. ThisY valve beingl closed, pipe 63 is blanked. The engineman next moves his enginemansbrakie valve to the lap position, thereby closing valve G. The yengi-ne- Pipev Ilo man then reverses valve A, thereby disconnecting pipe 67 from atmosphere and connecting this pipe with pipe G6. All avenues of escape are now closed 'for fluid pressure from chamber 2. 'lhe pressure supplied to this chamber through the restricted port i now gradually builds up. This pressure is, however, supplied to the stop reservoir 3 and in order to charge this reservoir a considerable interval of time is requiredl vWhen ,the stop reservoir, the pipe lines connected therewith, and the chamber 2 have been charged to the pressure required to reverse valve L', piston l returnsto its normal position. The engineman may then restore valve A to its normal position. If the engineman now moves his brake valve to the release or running position, valve G limmediately opens but this has no effect upon the rest of the apparatus, because all of the pipes which are connected with chamber Q of valve L are now disconnected from valve G.

If', however, the engineman leaves valve A in its reverse position after restoring valve L to its normal position and attempts to move the enginemans brake valve away from the lap position, the opening of valve Gr i1n mediately vents chamber 2 to atmosphere through pipes 64 and 66, valve A, pipes 67 and 42, and valve G. The apparatus is therefore so arranged that the engineman must return the release valve A to its normal position before he can proceed.

Although I have herein shown and described only two forms of railway traffic controlling apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention. Y 4

Having thus described my invention, what I claim is: v

l. The combination, in railway traffic controlling apparatus comprising a `pressure chamber, a valve member arranged to occupy a normal or a reverse position according as the pressure in said chamber is above or below a predetermined value, respectively, and means for constantly supplying fluid "pressure to said chamber through a restricted orifice, of a reservoir normally connected with atmosphere, means controlled by traffic conditions for at times disconnecting said reservoir from atmosphere and for connecting the reservoir with said chamber, means 'tor connecting said reservoir and said chamber with atmosphere when said valve member is in its reversed position, a manually operable valve for disconnecting said chamber from atmosphere and from said reservoir, and automatic brake applying mechanism controlled by said valve member.

2. Railway traiiic controlling apparatus comprising a train carried bra-ke application valve having a chamber constantly supplied with fiuid pressure through a restricted orilice, a port in said Yvalve normally closed but arranged to be opened when the pressure in said chamber is reduced below a predetermined value, automatic brake application mechanism controlled by said brake application valve, a manually operable release valve located on the train and having a normal and a reverse position, means responsive to traiiic conditions and enective when said release valve is in its normal position for reducing the pressure in said chamber below such predetermined value, and means including said port for subsequently connecting said chamber with atmosphere, said last mentioned means being ineffective when said release valve is in its reverse position.

3. Railway traffic controlling apparatus comprising` a brake application valve having a chamber constantly supplied with fluid pressure through a. restricted orifice, a nor-l mally closed port arrangedto be opened when the pressure in said chamber is reduced, a pipe, means responsive to trafiic conditions ttor-at time-i connecting said chamber vwith said pipe, a reservoir, a manually operable valve for at times connecting said pipe with said reservoir, and means including said port for at times connecting said reservoir with atmosphere.

et. Railway traiiic controlling apparatus comprising a brake application valve having a chamber constantly supplied with fluid pressure through a restricted orifice, a normally closed port arranged to be opened when the pressure in said chamber is reduced, a pipe, means for connecting said pipe with atmosphere or with said chamber according as trail-iel conditions are safe or dangerous, a reservoir connected with atmosphere. when said port is open, and a manually operable valve for at times connecting said pipe with said reservoir.

5. The con'ibination, in railway traffic controlling apparatus comprising an application valve having a pressure chamber constantly supplied with iiuid pressure through a restricted orifice and a slide valve respon- Asive to the pressure in said chamber; of a pilot valve arranged to be closed only when the enginemans brake valve is in the lap position, means controlled by said slide valve forattimes connecting said chamber with said pilot valve, a pipe, means for connecting said pipe with atmosphere or with said chamber depending upon traffic conditions, a

reservoir, means controlled by said slide valve for at times connecting said reservoir with atmosphere, and a manually operable valve for connecting said pipe with said reservoir or with said pilot valve. Y

6. The combination, inrailway traffic controlling apparatus comprising an application valve having apressure chamber constantly supplied with fluid pressure through pilot valve arranged tobe closed only when the enginemanls brake valve is in the lap p tion, means controlled by said slide valve 'for at times connecting lsaid chamber with said'pilot valve, a pipe, means for connecting said pipe with atmosphere or with said chamber depending upon trailic conditions, a reservoir, n'ieans'controlled by said slide valve lor at times connecting said reservoir with atmosphere, a manually operable valve arranged to connect Asaid pipe with said reservoir when such manually operable valve is in one position and to connect said piper with saidpilot valve when said manually operable valve isin the other position, and a check valve interposed between said pilot `valveand said manually operable valve,

7. The combination, in railway tra'liic cont olling apparatus comprising a brake application valve, and n'ieans responsive. to tratlie conditions iior at times moving said valve from its normal to its reverse'position; ot a pilot valve controlled in accordance with the position ot the enginemans brake valve, a manually controlled suppressingvalve, amanually operable release valve, and means effective when said brake applica- .tion valve is vinthe reverse position and controlledby. saidsuppressing valve and by said pilot valve and by said release valve for restoringsaid brake application valve to its normal position.

8. .The combination, in railway traffic controlling apparatus comprising an application valve having a pressure chamber constantly supplied with fluid pressure through a yrestricted oriiice and a slide valve arrangedxto occupy a normal or a reverse position depending upon the pressure in said chamber; ot' a pilot valve controlled in accordance with the position of the enginemans brake valve, means for at times reducing the pressurein said chamber whereby said slide valve moves to its reverse position, means effective when said slide valve is in its reverse position for connecting said chamber with atmosphere, a port in said slide valve open when the valve is-in its reverse position for connecting said chamber with said pilot valve, and a manually operable valve for at times connecting said chamber with said pilot valve independently of the posit-ion of said slide valve.

9. Railway traiiic controlling apparatus comprising a brake application valve having a chamber constantly supplied with -fluid pressure through a restricted orice and a slide valve controlled in accord-ance with the pressure in said chamber, a pilot valve communicating with atmosphere and controlled in accordance with the position of the enginemans'brake valve, means controlled by tratiic conditions orat times decreasing the pressure in said chamber, means controlled by said slide va'lve for connect-ing said chamber with said pilot valve and with atmosphere, and a manually operable valve for at times blanlring such connection to atmosphere and for connecting saidchamber directly with said pilot valve independently oi'said slide valve.

lO. Railway traiiic controlling apparatus comprising a brake application valve having a chamber constantly supplied with fluid pressure through a restricted orifice and a slide valve controlled in accordance with the pressure in said chamber, a pipe, a pilot valve controlled in accordance with the position ot `the enginemans brake valve for at times connecting said pipe with atmosphere, ieans controlled in accordance with traffic conditions Vtor at times decreasing the pressure in said chamber, means controlled by said slide valve lor at times connecting said pipe with said chamber, and a manually operable valve 'lor connecting said pipe with said chamber or with atmosphere depending upon the position ol such manually operable valve.

ll. Railway trallic controlling apparatus comprising a brake application valve having` a chamber constantly supplied with fluid pressure through a restricted orifice and slide valve controlledvin accordance with the pressure in said chamber, a pilot valve closed only when the enginemans brake valve is in the'lap position, pipe communieating` with atmosphere through said pilot valve, means Vcontrolled in accordance with trailic condie tions for at times decreasing the pressure in said chamber, means controlled by said slide valve -for at. times connectingl said pipe with said chamber, and a manually operable valve t'or selectively connecting said pipe with said chamber or with atmosphere.

l2. Railway traiiic controlling apparatus comprising a chamber normally supplied with fluid pressure, automatic bral-:e applying'mechanism on a train controlled in accordance with the pressure in said chamber, apilotvalve closed only when the enginemans brake valve is in a predetermined position, a manually operable valve capable of assuming a normal or a reverse position, means responsive to tratlic conditions for at times connecting said chamber with atmosphere through said manually operable valve in'its normallposition, and means effect-ive when said manually operable valve is in its reverse position for connecting said chamber with atmosphere through said pilot valve.

13. Railway traffic controlling apparatus comprising a. train carried brake application valve'having a chamber constantly supplied with iuid pressure through a restricted orilice, a slide valve arranged to occupy a nor- Sli mal or a reverse position depending upon the pressure in said chamber, automatic apparatus for applying the brakes when said slide valve is in its reverse position, a normally open manually operable valve, and means elfiiectivc upon a change from less restrictive to more restrictive traliic conditions in advance to connect said chamber with atmosphere through said manually operable valve, said means being effective upon a change from more restrictive to less restrictive conditions to disconnect said chamber from atmosphere independentlyof said manually operable valve.

let. Railway traffic controlling` apparatus comprising a brake application valve capable of assuming a normal or a reverse po si tion, means responsive to traic conditions for at times moving said brake applic-ation valve to its reverse position, a manually operable valve, means controlled by said brake application valve and effective when said manually operablevalve is normal but not when said manually operable valve is reversed to maintain said brake application valve in its reverse position7 and other means controlled by the enginemans brake valve and eiiective only ivlien the manually operable valve is reversed for causing` said brake application valve to occupy its reverse position.

l5. Railway traliic controlling` apparatus comprisingl a train carried brake application valve having a chamber constant-ly sup plied `with fluid pressure through a restricted orilice, a port in said valve normally closed but arranged to be opened when the pressure in raid chamber is reduced below a predetermined value, automatic brake application meclianisn'i controlled by said bralre application valve, a manually operable release valve on the train accessible to the engineman only when the train at restI and having a normal and a reverse position, means responsive to traliic conditions and eiective when said release valve is in its normal position for reducing the pressure in said chamber below such predetermined value, and means including, said port -tor subsequently connecting said chamber with atn'iosphere, said last mentioned means being ineil'ective when said release valve is in its reverse position,

ln testimony whereof I afl'lix my signal-ure.

HERBERT A. WALLACE. 

